C0387 Buick Code - Unable to Complete Shift
Quick Answer
The Transfer Case Motor, also known as the transfer case range actuator, is a bi-directional, permanent magnet, DC motor. Common causes include Faulty Transfer Case Motor (Transfer Case Two/Four Wheel Drive Actuator), Transfer Case Motor harness is open or shorted, Transfer Case Motor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- C0387 Buick indicates Unable to Complete Shift.
- Common causes
- Common causes include Faulty Transfer Case Motor (Transfer Case Two/Four Wheel Drive Actuator), Transfer Case Motor harness is open or shorted, Transfer Case Motor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code C0387 Buick Description
If the shift lever detent shaft were to bind, or there was a mechanical failure, or the transfer case clockwise circuit and the transfer case counterclockwise circuit were shorted together, the shift would not be completed. This will cause the Diagnostic Trouble Code (DTC) to be set in order to protect system components from damage.
What are the Possible Causes of the DTC C0387 Buick?
- Faulty Transfer Case Motor (Transfer Case Two/Four Wheel Drive Actuator)
- Transfer Case Motor harness is open or shorted
- Transfer Case Motor circuit poor electrical connection
How to Fix the DTC C0387 Buick?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the C0387 Buick code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about C0387 Buick Code
1. What does the OBDII code C0387 mean on a Buick?
C0387 indicates that the vehicle's transfer case control module has detected an issue preventing the completion of a requested shift, typically in the 4WD or AWD system.
2. What are the common symptoms of code C0387 in a Buick?
Common symptoms include the inability to shift into or out of 4WD/AWD modes, warning lights on the dashboard (such as "Service 4WD"), and possible clunking or grinding noises during shift attempts.
3. What causes the C0387 code on a Buick?
The code can be caused by a faulty transfer case shift motor, damaged transfer case gears, wiring issues, or a malfunctioning transfer case control module.
4. Can a bad transfer case motor trigger the C0387 code?
Yes, a bad or stuck transfer case shift motor is one of the most common causes of the C0387 code.
5. How can I diagnose the C0387 code on my Buick?
Diagnose the issue by checking the transfer case shift motor, inspecting wiring and connectors for damage or corrosion, and using a scan tool to monitor the transfer case control module’s data.
6. Is it safe to drive with the C0387 code active?
Driving with this code may be safe in some cases, but it could compromise 4WD/AWD functionality, which may be dangerous in certain road or weather conditions.
7. How is the C0387 code typically repaired?
Repairs may include replacing the transfer case shift motor, repairing or replacing damaged wiring, or reprogramming or replacing the transfer case control module.
8. Can a software issue cause the C0387 code on a Buick?
Yes, outdated or corrupted software in the transfer case control module can sometimes cause this code, requiring a reflash or software update.
9. How much does it typically cost to fix the C0387 code on a Buick?
The cost can vary but typically ranges from $200 to $600 depending on whether the issue is with the shift motor, wiring, or control module.
10. Can lack of maintenance lead to the C0387 code?
Yes, lack of proper maintenance, such as not servicing the transfer case fluid, can lead to mechanical issues that trigger this code.
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